neo-go/pkg/core/native/notary.go
2021-01-18 00:38:23 +03:00

437 lines
15 KiB
Go

package native
import (
"errors"
"fmt"
"math"
"math/big"
"sync"
"github.com/nspcc-dev/neo-go/pkg/core/dao"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/core/storage"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
// Notary represents Notary native contract.
type Notary struct {
interop.ContractMD
GAS *GAS
Desig *Designate
lock sync.RWMutex
// isValid defies whether cached values were changed during the current
// consensus iteration. If false, these values will be updated after
// blockchain DAO persisting. If true, we can safely use cached values.
isValid bool
maxNotValidBeforeDelta uint32
}
const (
notaryContractID = reservedContractID - 1
// NotaryVerificationPrice is the price of `verify` Notary method.
NotaryVerificationPrice = 100_0000
// prefixDeposit is a prefix for storing Notary deposits.
prefixDeposit = 1
defaultDepositDeltaTill = 5760
defaultMaxNotValidBeforeDelta = 140 // 20 rounds for 7 validators, a little more than half an hour
)
var maxNotValidBeforeDeltaKey = []byte{10}
// newNotary returns Notary native contract.
func newNotary() *Notary {
n := &Notary{ContractMD: *interop.NewContractMD(nativenames.Notary, notaryContractID)}
desc := newDescriptor("onPayment", smartcontract.VoidType,
manifest.NewParameter("from", smartcontract.Hash160Type),
manifest.NewParameter("amount", smartcontract.IntegerType),
manifest.NewParameter("data", smartcontract.AnyType))
md := newMethodAndPrice(n.onPayment, 100_0000, callflag.WriteStates)
n.AddMethod(md, desc)
desc = newDescriptor("lockDepositUntil", smartcontract.BoolType,
manifest.NewParameter("address", smartcontract.Hash160Type),
manifest.NewParameter("till", smartcontract.IntegerType))
md = newMethodAndPrice(n.lockDepositUntil, 100_0000, callflag.WriteStates)
n.AddMethod(md, desc)
desc = newDescriptor("withdraw", smartcontract.BoolType,
manifest.NewParameter("from", smartcontract.Hash160Type),
manifest.NewParameter("to", smartcontract.Hash160Type))
md = newMethodAndPrice(n.withdraw, 100_0000, callflag.WriteStates)
n.AddMethod(md, desc)
desc = newDescriptor("balanceOf", smartcontract.IntegerType,
manifest.NewParameter("addr", smartcontract.Hash160Type))
md = newMethodAndPrice(n.balanceOf, 100_0000, callflag.ReadStates)
n.AddMethod(md, desc)
desc = newDescriptor("expirationOf", smartcontract.IntegerType,
manifest.NewParameter("addr", smartcontract.Hash160Type))
md = newMethodAndPrice(n.expirationOf, 100_0000, callflag.ReadStates)
n.AddMethod(md, desc)
desc = newDescriptor("verify", smartcontract.BoolType,
manifest.NewParameter("signature", smartcontract.SignatureType))
md = newMethodAndPrice(n.verify, 100_0000, callflag.ReadStates)
n.AddMethod(md, desc)
desc = newDescriptor("getMaxNotValidBeforeDelta", smartcontract.IntegerType)
md = newMethodAndPrice(n.getMaxNotValidBeforeDelta, 100_0000, callflag.ReadStates)
n.AddMethod(md, desc)
desc = newDescriptor("setMaxNotValidBeforeDelta", smartcontract.BoolType,
manifest.NewParameter("value", smartcontract.IntegerType))
md = newMethodAndPrice(n.setMaxNotValidBeforeDelta, 300_0000, callflag.WriteStates)
n.AddMethod(md, desc)
return n
}
// Metadata implements Contract interface.
func (n *Notary) Metadata() *interop.ContractMD {
return &n.ContractMD
}
// Initialize initializes Notary native contract and implements Contract interface.
func (n *Notary) Initialize(ic *interop.Context) error {
n.isValid = true
n.maxNotValidBeforeDelta = defaultMaxNotValidBeforeDelta
return nil
}
// OnPersist implements Contract interface.
func (n *Notary) OnPersist(ic *interop.Context) error {
var (
nFees int64
notaries keys.PublicKeys
err error
)
for _, tx := range ic.Block.Transactions {
if tx.HasAttribute(transaction.NotaryAssistedT) {
if notaries == nil {
notaries, err = n.GetNotaryNodes(ic.DAO)
if err != nil {
return fmt.Errorf("failed to get notary nodes: %w", err)
}
}
nKeys := tx.GetAttributes(transaction.NotaryAssistedT)[0].Value.(*transaction.NotaryAssisted).NKeys
nFees += int64(nKeys) + 1
if tx.Sender() == n.Hash {
payer := tx.Signers[1]
balance := n.GetDepositFor(ic.DAO, payer.Account)
balance.Amount.Sub(balance.Amount, big.NewInt(tx.SystemFee+tx.NetworkFee))
if balance.Amount.Sign() == 0 {
err := n.removeDepositFor(ic.DAO, payer.Account)
if err != nil {
return fmt.Errorf("failed to remove an empty deposit for %s from storage: %w", payer.Account.StringBE(), err)
}
} else {
err := n.putDepositFor(ic.DAO, balance, payer.Account)
if err != nil {
return fmt.Errorf("failed to update deposit for %s: %w", payer.Account.StringBE(), err)
}
}
}
}
}
if nFees == 0 {
return nil
}
singleReward := calculateNotaryReward(nFees, len(notaries))
for _, notary := range notaries {
n.GAS.mint(ic, notary.GetScriptHash(), singleReward, false)
}
return nil
}
// PostPersist implements Contract interface.
func (n *Notary) PostPersist(ic *interop.Context) error {
n.lock.Lock()
defer n.lock.Unlock()
if n.isValid {
return nil
}
n.maxNotValidBeforeDelta = getUint32WithKey(n.ContractID, ic.DAO, maxNotValidBeforeDeltaKey, defaultMaxNotValidBeforeDelta)
n.isValid = true
return nil
}
// onPayment records deposited amount as belonging to "from" address with a lock
// till the specified chain's height.
func (n *Notary) onPayment(ic *interop.Context, args []stackitem.Item) stackitem.Item {
if h := ic.VM.GetCallingScriptHash(); h != n.GAS.Hash {
panic(fmt.Errorf("only GAS can be accepted for deposit, got %s", h.StringBE()))
}
from := toUint160(args[0])
to := from
amount := toBigInt(args[1])
data, ok := args[2].(*stackitem.Array)
if !ok || len(data.Value().([]stackitem.Item)) != 2 {
panic(errors.New("`data` parameter should be an array of 2 elements"))
}
additionalParams := data.Value().([]stackitem.Item)
if !additionalParams[0].Equals(stackitem.Null{}) {
to = toUint160(additionalParams[0])
}
allowedChangeTill := ic.Tx.Sender() == to
currentHeight := ic.Chain.BlockHeight()
deposit := n.GetDepositFor(ic.DAO, to)
till := toUint32(additionalParams[1])
if till < currentHeight {
panic(fmt.Errorf("`till` shouldn't be less then the chain's height %d", currentHeight))
}
if deposit != nil && till < deposit.Till {
panic(fmt.Errorf("`till` shouldn't be less then the previous value %d", deposit.Till))
}
if deposit == nil {
if amount.Cmp(big.NewInt(2*transaction.NotaryServiceFeePerKey)) < 0 {
panic(fmt.Errorf("first deposit can not be less then %d, got %d", 2*transaction.NotaryServiceFeePerKey, amount.Int64()))
}
deposit = &state.Deposit{
Amount: new(big.Int),
}
if !allowedChangeTill {
till = currentHeight + defaultDepositDeltaTill
}
} else if !allowedChangeTill { // only deposit's owner is allowed to set or update `till`
till = deposit.Till
}
deposit.Amount.Add(deposit.Amount, amount)
deposit.Till = till
if err := n.putDepositFor(ic.DAO, deposit, to); err != nil {
panic(fmt.Errorf("failed to put deposit for %s into the storage: %w", from.StringBE(), err))
}
return stackitem.Null{}
}
// lockDepositUntil updates the chain's height until which deposit is locked.
func (n *Notary) lockDepositUntil(ic *interop.Context, args []stackitem.Item) stackitem.Item {
addr := toUint160(args[0])
ok, err := runtime.CheckHashedWitness(ic, addr)
if err != nil {
panic(fmt.Errorf("failed to check witness for %s: %w", addr.StringBE(), err))
}
if !ok {
return stackitem.NewBool(false)
}
till := toUint32(args[1])
if till < ic.Chain.BlockHeight() {
return stackitem.NewBool(false)
}
deposit := n.GetDepositFor(ic.DAO, addr)
if deposit == nil {
return stackitem.NewBool(false)
}
if till < deposit.Till {
return stackitem.NewBool(false)
}
deposit.Till = till
err = n.putDepositFor(ic.DAO, deposit, addr)
if err != nil {
panic(fmt.Errorf("failed to put deposit for %s into the storage: %w", addr.StringBE(), err))
}
return stackitem.NewBool(true)
}
// withdraw sends all deposited GAS for "from" address to "to" address.
func (n *Notary) withdraw(ic *interop.Context, args []stackitem.Item) stackitem.Item {
from := toUint160(args[0])
ok, err := runtime.CheckHashedWitness(ic, from)
if err != nil {
panic(fmt.Errorf("failed to check witness for %s: %w", from.StringBE(), err))
}
if !ok {
return stackitem.NewBool(false)
}
to := from
if !args[1].Equals(stackitem.Null{}) {
to = toUint160(args[1])
}
deposit := n.GetDepositFor(ic.DAO, from)
if deposit == nil {
return stackitem.NewBool(false)
}
if ic.Chain.BlockHeight() < deposit.Till {
return stackitem.NewBool(false)
}
cs, err := ic.GetContract(n.GAS.Hash)
if err != nil {
panic(fmt.Errorf("failed to get GAS contract state: %w", err))
}
transferArgs := []stackitem.Item{stackitem.NewByteArray(n.Hash.BytesBE()), stackitem.NewByteArray(to.BytesBE()), stackitem.NewBigInteger(deposit.Amount), stackitem.Null{}}
err = contract.CallFromNative(ic, n.Hash, cs, "transfer", transferArgs, true)
if err != nil {
panic(fmt.Errorf("failed to transfer GAS from Notary account: %w", err))
}
if !ic.VM.Estack().Pop().Bool() {
panic("failed to transfer GAS from Notary account: `transfer` returned false")
}
if err := n.removeDepositFor(ic.DAO, from); err != nil {
panic(fmt.Errorf("failed to remove withdrawn deposit for %s from the storage: %w", from.StringBE(), err))
}
return stackitem.NewBool(true)
}
// balanceOf returns deposited GAS amount for specified address.
func (n *Notary) balanceOf(ic *interop.Context, args []stackitem.Item) stackitem.Item {
acc := toUint160(args[0])
return stackitem.NewBigInteger(n.BalanceOf(ic.DAO, acc))
}
// BalanceOf is an internal representation of `balanceOf` Notary method.
func (n *Notary) BalanceOf(dao dao.DAO, acc util.Uint160) *big.Int {
deposit := n.GetDepositFor(dao, acc)
if deposit == nil {
return big.NewInt(0)
}
return deposit.Amount
}
// expirationOf Returns deposit lock height for specified address.
func (n *Notary) expirationOf(ic *interop.Context, args []stackitem.Item) stackitem.Item {
acc := toUint160(args[0])
return stackitem.Make(n.ExpirationOf(ic.DAO, acc))
}
// ExpirationOf is an internal representation of `expirationOf` Notary method.
func (n *Notary) ExpirationOf(dao dao.DAO, acc util.Uint160) uint32 {
deposit := n.GetDepositFor(dao, acc)
if deposit == nil {
return 0
}
return deposit.Till
}
// verify checks whether the transaction was signed by one of the notaries.
func (n *Notary) verify(ic *interop.Context, args []stackitem.Item) stackitem.Item {
sig, err := args[0].TryBytes()
if err != nil {
panic(fmt.Errorf("failed to get signature bytes: %w", err))
}
tx := ic.Tx
if len(tx.GetAttributes(transaction.NotaryAssistedT)) == 0 {
return stackitem.NewBool(false)
}
for _, signer := range tx.Signers {
if signer.Account == n.Hash {
if signer.Scopes != transaction.None {
return stackitem.NewBool(false)
}
}
}
if tx.Sender() == n.Hash {
if len(tx.Signers) != 2 {
return stackitem.NewBool(false)
}
payer := tx.Signers[1].Account
balance := n.GetDepositFor(ic.DAO, payer)
if balance == nil || balance.Amount.Cmp(big.NewInt(tx.NetworkFee+tx.SystemFee)) < 0 {
return stackitem.NewBool(false)
}
}
notaries, err := n.GetNotaryNodes(ic.DAO)
if err != nil {
panic(fmt.Errorf("failed to get notary nodes: %w", err))
}
hash := tx.GetSignedHash().BytesBE()
var verified bool
for _, n := range notaries {
if n.Verify(sig, hash) {
verified = true
break
}
}
return stackitem.NewBool(verified)
}
// GetNotaryNodes returns public keys of notary nodes.
func (n *Notary) GetNotaryNodes(d dao.DAO) (keys.PublicKeys, error) {
nodes, _, err := n.Desig.GetDesignatedByRole(d, RoleP2PNotary, math.MaxUint32)
return nodes, err
}
// getMaxNotValidBeforeDelta is Notary contract method and returns the maximum NotValidBefore delta.
func (n *Notary) getMaxNotValidBeforeDelta(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
return stackitem.NewBigInteger(big.NewInt(int64(n.GetMaxNotValidBeforeDelta(ic.DAO))))
}
// GetMaxNotValidBeforeDelta is an internal representation of Notary getMaxNotValidBeforeDelta method.
func (n *Notary) GetMaxNotValidBeforeDelta(dao dao.DAO) uint32 {
n.lock.RLock()
defer n.lock.RUnlock()
if n.isValid {
return n.maxNotValidBeforeDelta
}
return getUint32WithKey(n.ContractID, dao, maxNotValidBeforeDeltaKey, defaultMaxNotValidBeforeDelta)
}
// setMaxNotValidBeforeDelta is Notary contract method and sets the maximum NotValidBefore delta.
func (n *Notary) setMaxNotValidBeforeDelta(ic *interop.Context, args []stackitem.Item) stackitem.Item {
value := toUint32(args[0])
if value > transaction.MaxValidUntilBlockIncrement/2 || value < uint32(ic.Chain.GetConfig().ValidatorsCount) {
panic(fmt.Errorf("MaxNotValidBeforeDelta cannot be more than %d or less than %d", transaction.MaxValidUntilBlockIncrement/2, ic.Chain.GetConfig().ValidatorsCount))
}
ok, err := checkValidators(ic)
if err != nil {
panic(fmt.Errorf("failed to check committee signature: %w", err))
}
if !ok {
return stackitem.NewBool(false)
}
n.lock.Lock()
defer n.lock.Unlock()
err = setUint32WithKey(n.ContractID, ic.DAO, maxNotValidBeforeDeltaKey, value)
if err != nil {
panic(fmt.Errorf("failed to put value into the storage: %w", err))
}
n.isValid = false
return stackitem.NewBool(true)
}
// GetDepositFor returns state.Deposit for the account specified. It returns nil in case if
// deposit is not found in storage and panics in case of any other error.
func (n *Notary) GetDepositFor(dao dao.DAO, acc util.Uint160) *state.Deposit {
key := append([]byte{prefixDeposit}, acc.BytesBE()...)
deposit := new(state.Deposit)
err := getSerializableFromDAO(n.ContractID, dao, key, deposit)
if err == nil {
return deposit
}
if err == storage.ErrKeyNotFound {
return nil
}
panic(fmt.Errorf("failed to get deposit for %s from storage: %w", acc.StringBE(), err))
}
// putDepositFor puts deposit on the balance of the specified account in the storage.
func (n *Notary) putDepositFor(dao dao.DAO, deposit *state.Deposit, acc util.Uint160) error {
key := append([]byte{prefixDeposit}, acc.BytesBE()...)
return putSerializableToDAO(n.ContractID, dao, key, deposit)
}
// removeDepositFor removes deposit from the storage.
func (n *Notary) removeDepositFor(dao dao.DAO, acc util.Uint160) error {
key := append([]byte{prefixDeposit}, acc.BytesBE()...)
return dao.DeleteStorageItem(n.ContractID, key)
}
// calculateNotaryReward calculates the reward for a single notary node based on FEE's count and Notary nodes count.
func calculateNotaryReward(nFees int64, notariesCount int) *big.Int {
return big.NewInt(nFees * transaction.NotaryServiceFeePerKey / int64(notariesCount))
}